Rheumatoid arthritis and osteoarthritis are different types of arthritis. They share some similar characteristics, but each has different symptoms and requires different treatment. So an accurate diagnosis is important.
Osteoarthritis is the most common type of arthritis, it is the number one cause of disability in the United States. Osteoarthritis occurs when the cartilage covering the end of the bones gradually breaks down, or degenerates, with age or overuse. For this reason, osteoarthritis is sometimes called degenerative joint disease. Osteoarthritis usually causes pain and limited motion, and is most common in the knee joint and hip joint. In early stages, osteoarthritis is often asymmetric with only partially degenerated joint surfaces. Joints damaged by osteoarthritis may be stiff in the morning, but they usually feel better in about 20 minutes.
Each of the joints in the human body contains synovial fluid which is the clear, viscous, lubricating fluid secreted by synovial membranes. Synovial fluid lubricates the joint and allows for ease of movement. Rheumatoid arthritis is a systemic, autoimmune condition that causes the normally thin synovial membrane (synovium) to become inflamed and thickened, leading to an accumulation of synovial fluid and causing pain and swelling. Joint erosion may follow. Rheumatoid arthritis most commonly affects the joints of the hands and feet, but can also cause elbow, shoulder, and neck problems. The joints are often affected in a fairly symmetrical fashion and often hurt for more than one hour after you get out of bed.In severe cases, rheumatoid arthritis can affect other areas of the body, such as the skin, eyes, lungs, and nerves.Rheumatoid arthritis affects about one-tenth as many people as osteoarthritis.